WARNING

This lens exploits a put ambiguity since apt.conf allows for both APT { Clean-Installed { “true” } } and APT::Clean-Installed “true”; but we’re choosing to map them the same way

The recursive lens doesn’t seem to care and defaults to the first item in the union.

This is why the APT { Clean-Installed { “true”; } } form is listed first, since it supports all subnodes (which Dpkg::Conf) doesn’t.

Exchanging these two expressions in the union makes tests fails since the tree cannot be mapped back.

This situation results in existing configuration being modified when the associated tree is modified. For example, changing the value of APT::Clean-Installed “true”; to “false” results in APT { Clean-Installed “false”; }